These results point to the importance of dilution factor and the de- pendence of MDL on the dilution factor. For example, a dilution factor of 1:30 resulted in an MDL value of 1.2 mg/L for Hydrex 3572. In con- trast, increasing the dilution ratio to 1:50 resulted in an MDL value of 0.25 mg/L for the same polymer. These results indicate that by opti- mizing the dilution factor, the detection limits can be improved even further. Dilution should aim to bring down the sample absorbance to the working range of the instrument. At a dilution rate of 1:30,